Image processing method and apparatus for autostereoscopic three-dimensional display

ABSTRACT

A three-dimensional (3D) image providing method and apparatus is provided. The 3D image providing method includes detecting an eye location of a viewer and providing a 3D image based on the detected eye location, in which the providing of the 3D image includes determining an image pixel value corresponding to a display pixel of a display panel, determining a luminance weight corresponding to the display pixel based on a ray direction of a ray output from the display pixel and the detected eye location, applying the luminance weight to the image pixel value corresponding to the display pixel, and outputting, through the display pixel, the image pixel value with the luminance weight applied thereto.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority from Korean Patent Application No.10-2017-0116735 filed on Sep. 12, 2017 in the Korean IntellectualProperty Office, the disclosure of which is incorporated herein byreference in its entirety.

BACKGROUND 1. Field

Methods and apparatuses consistent with example embodiments relate toimage processing technology for an autostereoscopic three-dimensional(3D) display.

2. Description of the Related Art

To effectively express a three-dimensional (3D) image that provides astereoscopic sense, images of different viewpoints may need to beprovided respectively to both eyes of a viewer (also referred to as auser). A method of displaying different images to both eyes of a usermay include, for example, a glass-type or stereoscopic method to obtaina desired image through filtering using polarization-based division,time division, or wavelength division of varying a wavelength of aprimary color, and a glassless-type or autostereoscopic method todisplay an image at each viewpoint in a space using a 3D optical devicesuch as, for example, a parallax barrier, a lenticular lens, and adirectional backlight unit.

SUMMARY

Example embodiments provide methods and apparatuses that relate to imageprocessing technology for an autostereoscopic three-dimensional (3D)display.

According to an aspect of an example embodiment, there is provided a 3Dimage providing method including detecting an eye location of a viewer,and providing a 3D image based on the detected eye location, wherein theproviding of the 3D image includes determining an image pixel valuecorresponding to a display pixel included in a display panel,determining a luminance weight corresponding to the display pixel basedon a ray direction of a ray output from the display pixel and thedetected eye location, applying the determined luminance weight to theimage pixel value corresponding to the display pixel, and outputting,through the display pixel, the image pixel value with the determinedluminance weight applied thereto.

The determining the luminance weight based on at least one of a firstreference value corresponding to a distance between a pass-through pointof the ray direction and a location of a left eye of the viewer, or asecond reference value corresponding to a distance between the raydirection and a location of a right eye of the viewer, the pass-throughpoint of the ray direction being a location where the ray crosses a linepassing through the location of the left eye and the location of theright eye.

The determining of the luminance weight may include determining apredefined luminance weight among a plurality of predefined luminanceweights to be the luminance weight based on the at least one of thefirst reference value or the second reference value.

The determining of the luminance weight may include determining a firstluminance weight to be the luminance weight corresponding to the displaypixel in response to the first reference value being included in a firstreference value range based on the location of the left eye or thesecond reference value being included in a second reference value rangebased on the location of the right eye.

The determining of the luminance weight may include determining a secondluminance weight to be the luminance weight corresponding to the displaypixel in response to the first reference value being outside of thefirst reference value range and the second reference value being outsideof the second reference value range, wherein the first luminance weightis greater than the second luminance weight.

The magnitude of the first reference value range may be equal to amagnitude of the second reference value range.

The first reference value may correspond to a difference between the raydirection and a direction of a line from the display pixel towards thelocation of the left eye, and the second reference value may correspondto a difference between the ray direction and a direction of a line fromthe display pixel towards the location of the right eye.

The first reference value may be determined based on an angle betweenthe ray direction and the direction of the line from the display pixeltowards the location of the left eye, or a distance between thepass-through point of the ray direction and the location of the lefteye, and the second reference value may be determined based on an anglebetween the ray direction and the direction of the line from the displaypixel towards the location of the right eye, or a distance between thepass through point of the ray direction and the location of the righteye.

The luminance of the image pixel value to be output through the displaypixel may be adjusted based on the luminance weight to be applied to theimage pixel value.

The determining of the image pixel value may include allocating, to thedisplay pixel, an image pixel value of one of a left-view image and aright-view image based on the detected eye location.

The determining of the image pixel value may further include adjusting aleft luminance range of image pixels of the left-view image and a rightluminance range of image pixels of the right-view image based on apredefined luminance scaling value, and adjusting a luminance value ofeach of the image pixels of the left-view image with the adjusted leftluminance range and a luminance value of each of the image pixels of theright-view image with the adjusted right luminance range, based on apredefined crosstalk correction value.

The determining of the image pixel value may further include allocatingthe image pixel value of the left-view image with the adjusted leftluminance value to the display pixel in response to a distance between apass-through point of the ray direction and a location of a left eye ofthe viewer being smaller than a distance between the pass-through pointof the ray direction and a location of a right eye of the viewer, thepass-through point of the ray direction being a location where the raycrosses a line passing through the location of the left eye and thelocation of the right eye, and allocating the image pixel value of theright-view image with the adjusted right luminance value to the displaypixel in response to the distance between the pass-through point of theray direction and the location of the right eye being smaller than thedistance between the pass-through point of the ray direction and thelocation of the left eye.

A non-transitory computer-readable storage medium storing instructionsthat, when executed by a processor, may cause the processor to performthe 3D image providing method.

According to an aspect of another example embodiment, there is provideda 3D image providing apparatus including an eye location detectorconfigured to detect an eye location of a viewer, a processor configuredto generate a panel image based on the detected eye location, and adisplay panel configured to output a 3D image based on the generatedpanel image, wherein the processor is further configured to determine aluminance weight corresponding to a display pixel of the display panelbased on a ray direction of a ray output from the display pixel and thedetected eye location, apply the determined luminance weight to an imagepixel value corresponding to the display pixel, and generate the panelimage based on the image pixel value with the luminance weight appliedthereto.

The processor may be further configured to determine the luminanceweight based on at least one of a first reference value corresponding toa distance between the ray direction and a location of a left eye of theviewer, or a second reference value corresponding to a distance betweenthe ray direction and a location of a right eye of the viewer.

The processor may be further configured to determine a predefinedluminance weight among a plurality of predefined luminance weights to bethe luminance weight corresponding to the display pixel based on atleast one of the first reference value or the second reference value.

The processor may be further configured to adjust a left luminance rangeof image pixels of a left-view image and a right luminance range ofimage pixels of a right-view image based on a predefined luminancescaling value, and adjust a luminance value of each of the image pixelsof the left-view image based on the adjusted left luminance range and aluminance value of each of the image pixels of the right-view imagebased on the adjusted right luminance range, based on a predefinedcrosstalk correction value.

The processor may be further configured to allocate an image pixel valueof the left-view image with the adjusted left luminance value to thedisplay pixel in response to a distance between a pass-through point ofthe ray direction and a location of a left eye of the viewer beingsmaller than a distance between the pass-through point of the raydirection and a location of a right eye of the viewer, the pass-throughpoint of the ray direction being a location where the ray crosses a linepassing through the location of the left eye and the location of theright eye, and allocate an image pixel value of the right-view imagewith the adjusted right luminance value to the display pixel in responseto the distance between the pass-through point of the ray direction andthe location of the right eye being smaller than the distance betweenthe pass-through point of the ray direction and the location of the lefteye.

The display panel may include a parallax barrier or a lenticular lens.

According to an aspect of another example embodiment, there is provideda 3D image providing method including detecting a right eye location anda left eye location of a viewer, and providing a 3D image based on thedetected right eye location and the detected left eye location, whereinthe providing of the 3D image includes determining an image pixel valuecorresponding to a display pixel included in a display panel byallocating an image pixel value of one of a left-view image and aright-view image to the display pixel based on the detected right eyelocation and the detected left eye location, adjusting a left luminancerange of image pixels of the left-view image and a right luminance rangeof image pixels of the right-view image based on a predefined luminancescaling value, and adjusting a luminance value of each of the imagepixels of the left-view image with the adjusted left luminance range anda luminance value of each of the image pixels of the right-view imagewith the adjusted right luminance range, based on a predefined crosstalkcorrection value, determining a luminance weight corresponding to thedisplay pixel based on a ray direction of a ray output from the displaypixel and the detected right eye location and the detected left eyelocation, applying the determined luminance weight to the image pixelvalue corresponding to the display pixel, and outputting, through thedisplay pixel, the image pixel value with the determined luminanceweight applied thereto.

The determining of the image pixel value may further include in responseto a distance between a pass-through point of the ray direction and alocation of a left eye of the viewer being smaller than a distancebetween the pass-through point of the ray direction and a location of aright eye of the viewer, allocating the image pixel value of theleft-view image with the adjusted left luminance value to the displaypixel, the pass-through point of the ray direction being a locationwhere the ray crosses a line passing through the location of the lefteye and the location of the right eye, and in response to the distancebetween the pass-through point of the ray direction and the location ofthe right eye being smaller than the distance between the pass-throughpoint of the ray direction and the location of the left eye, allocatingthe image pixel value of the right-view image with the adjusted rightluminance value to the display pixel.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and/or other aspects will be more apparent and more readilyappreciated from the following description of example embodiments, takenin conjunction with the accompanying drawings of which:

FIG. 1 is a diagram illustrating a three-dimensional (3D) imageproviding apparatus according to an example embodiment;

FIG. 2 is a diagram illustrating a conversion process to generate a 3Dimage according to an example embodiment;

FIGS. 3 through 5 are flowcharts illustrating a 3D image providingmethod according to an example embodiment;

FIGS. 6A and 6B are diagrams illustrating examples determining a firstreference value and a second reference value based on a ray direction ofa display pixel and an eye location of a viewer according to an exampleembodiment;

FIG. 7 is a diagram illustrating an example of merging viewpointinformation in a tracking-type autostereoscopic 3D display deviceaccording to an example embodiment;

FIGS. 8A and 8B, and FIGS. 9A and 9B are diagrams illustrating examplesof determining a luminance weight based on an eye location of a vieweraccording to an example embodiment;

FIG. 10 is a diagram illustrating a 3D image rendering apparatusaccording to an example embodiment;

FIG. 11 is a diagram illustrating a configuration of a 3D imageproviding apparatus according to an example embodiment; and

FIG. 12 is a flowchart illustrating a 3D image providing methodaccording to an example embodiment.

DETAILED DESCRIPTION

Reference will now be made in detail to example embodiments, examples ofwhich are illustrated in the accompanying drawings, wherein likereference numerals refer to the like elements throughout. Exampleembodiments are described below in order to explain the presentdisclosure by referring to the figures.

The following structural or functional descriptions are exemplary tomerely describe the example embodiments, and the scope of the exampleembodiments is not limited to the descriptions provided in the presentdisclosure. Various changes and modifications can be made thereto bythose of ordinary skill in the art.

Although terms of “first” or “second” are used to explain variouscomponents, the components are not limited to the terms. These termsshould be used only to distinguish one component from another component.For example, a “first” component may be referred to as a “second”component, or similarly, and the “second” component may be referred toas the “first” component within the scope of the right according to theconcept of the present disclosure.

It will be understood that when a component is referred to as being“connected to” another component, the component can be directlyconnected or coupled to the other component or intervening componentsmay be present.

It should be further understood that the terms “comprises” and/or“comprising,” when used in this specification, specify the presence ofstated features, integers, steps, operations, elements, components or acombination thereof, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof.

Unless otherwise defined herein, all terms used herein includingtechnical or scientific terms have the same meanings as those generallyunderstood by one of ordinary skill in the art. Terms defined indictionaries generally used should be construed to have meaningsmatching with contextual meanings in the related art and are not to beconstrued as an ideal or excessively formal meaning unless otherwisedefined herein.

FIG. 1 is a diagram illustrating a three-dimensional (3D) imageproviding apparatus according to an example embodiment.

Referring to FIG. 1, a 3D image providing apparatus 110 may provide a 3Dimage to a viewer 120. The 3D image providing apparatus 110 refers to anapparatus configured to convert an input image to a 3D image, which is astereoscopic image, and output the 3D image. The 3D image providingapparatus may be an autostereoscopic 3D display device that may embodysuch a stereoscopic image using a 3D optical device such as, forexample, a parallax barrier and a lenticular lens. The 3D imageproviding apparatus 110 may perform 3D rendering to generate a panelimage to be transmitted to a display panel, convert the generated panelimage to the stereoscopic image through the 3D optical device, andoutput the stereoscopic image. The display panel may include a displaymodule, for example, a liquid crystal display (LCD), a light-emittingdiode (LED), an organic LED (OLED), and the like. The 3D image providingapparatus 110 may provide the viewer 120 a stereoscopic sense byallowing the viewer 120 to view different images with a left eye and aright eye of the viewer 120, respectively. The 3D image providingapparatus 110 may be any one of various types of display devices thatmay output a 3D image autostereoscopically or without glasses. Forexample, the 3D image providing apparatus 110 may be of any typeincluding, for example, a 3D television (TV), a glass-type wearabledevice, a 3D head-up display (HUD), a monitor, a tablet computer, asmartphone, a mobile device, a smart home appliance, etc.

FIG. 2 is a diagram illustrating a conversion process to generate a 3Dimage according to an example embodiment.

Referring to FIG. 2, a 3D image providing apparatus may output light, ora ray of light, that is output from each of display pixels 215 of adisplay panel 210 to a 3D space in a plurality of viewing directionsthrough a 3D optical device 220. The rays output from the display pixels215 may form a lightfield. A display pixel is included in the displaypanel 210, which may output a pixel value of an image pixel, or an imagepixel value. An image pixel is included in a panel image, which may havean image pixel value to be output through a display pixel correspondingto the image pixel. The display pixel may be provided in a form ofhardware, and the image pixel may be provided in a form of data. The rayof light to be output from each of the display pixels 215 may betransmitted in a certain direction through the 3D optical device 220.

The 3D optical device 220 may include, for example, a lenticular lens asillustrated in FIG. 2, or a parallax barrier. The lenticular lens or theparallax barrier may be designed to obliquely cross an array of thedisplay pixels 215 included in the display panel 210. Anautostereoscopic 3D display, such as the 3D image providing apparatus,may emit images of different viewpoints to both eyes of a viewer, forexample, a left eye 51 and a right eye 52 of a viewer such that theviewer experiences a stereoscopic sense or a 3D effect. For example, the3D image providing apparatus may allow the viewer to view a firstviewpoint image with the left eye 51 and a second viewpoint image withthe right eye 52, and thus provide a stereoscopic 3D image to theviewer. The stereoscopic sense may be generated by, for example, abinocular parallax.

When the 3D image providing apparatus provides a 3D image, the 3D imageproviding apparatus may track a viewpoint or an eye location of theviewer using, for example, a camera, and render the 3D image in realtime based on the tracked viewpoint or eye location. Thus, the 3D imageproviding apparatus may function as a viewpoint trackingautostereoscopic 3D display. Such a viewpoint tracking autostereoscopic3D display may render, in real time, a 3D image based on a viewinglocation of the viewer, and output two viewpoint images including aleft-view image and a right-view image to the viewing location.

The 3D image providing apparatus may render a 3D image in real timebased on a viewing location of the viewer, and thus enable real-timeprocessing of the 3D image. According to an example embodiment, an arrayof image pixels included in a panel image may be provided in a form of acombination of a pixel value of the left-view image and a pixel value ofthe right-view image. The two viewpoint images—the left-view image andthe right-view image—may form a lightfield, and be output to a viewingregion through a 3D optical device. An image into which the left-viewimage output in a plurality of directions is merged may be viewed by aleft eye of the viewer, and an image into which the right-view imageoutput in a plurality of directions is merged may be viewed by a righteye of the viewer.

Examples to be described hereinafter may be applied to enhance a qualityof a 3D image to be output through the viewpoint trackingautostereoscopic 3D display. For example, a crosstalk of the 3D imagethat may be viewed by both eyes of a viewer may be reduced. Thecrosstalk may occur when an image to be viewed by a left eye of a vieweris actually viewed by a right eye of the viewer or an image to be viewedby the right eye is actually viewed by the left eye, and may be causedby an incomplete separation between the image to be viewed by the lefteye and the image to be viewed by the right eye. In general, there aretwo main causes of such a crosstalk occurring in the autostereoscopic 3Ddisplay. One type of crosstalk is an offset crosstalk caused bydiffraction or scattering of light that may be generated when light istransmitted from the display through a 3D optical device, adhesive layersuch as glue, or a display pixel structure. The offset crosstalk mayoccur evenly throughout a display panel irrespective of a location ofthe viewer. Second type of crosstalk is a 3D pixel crosstalk that may becaused due to an error occurring in designing or manufacturing a 3Doptical device. The 3D pixel crosstalk may occur due to an error of, forexample, a slit size of a parallax barrier, or a slanted angle or a lensaberration of a lenticular lens.

The crosstalk may greatly affect a quality of a 3D image, and thus it isdesirable to reduce the crosstalk. The viewpoint trackingautostereoscopic 3D display may reduce the crosstalk through imageprocessing to be described hereinafter. According to an exampleembodiment, the viewpoint tracking autostereoscopic 3D display mayreceive a luminance scaling value and a crosstalk correction value asparameters, and perform 3D rendering based on the parameters to reducean influence of an offset crosstalk and enable real-time processing. Inaddition, in the real-time 3D rendering for each image pixel, theviewpoint tracking autostereoscopic 3D display may adjust a luminancecomponent to reduce an influence of a 3D pixel crosstalk. According toan example embodiment, in the 3D rendering, the viewpoint trackingautostereoscopic 3D display may reduce a complexity of image processingand enable high-speed processing through parallel processing for eachimage pixel. Hereinafter, a 3D image providing method to be performed bythe 3D image providing apparatus will be described in greater detailwith reference to the following drawings.

FIGS. 3 through 5 are flowcharts illustrating a 3D image providingmethod according to an example embodiment.

Referring to FIG. 3, in operation 310, a 3D image providing apparatusdetects an eye location of a viewer. The 3D image providing apparatusdetermines the eye location of the viewer by capturing an image in frontof the 3D image providing apparatus using a camera, and analyzing thecaptured image. For example, the 3D image providing apparatus may detecta feature point associated with an eye region in the image captured bythe camera, and determine the eye location of the viewer based on alocation of the detected feature point. The 3D image providing apparatusmay also determine the eye location using a neural network-baseddetector that is trained to output an eye location from an input image.However, embodiments are not limited thereto, and the 3D image providingapparatus may detect the eye location using other methods.

In operation 320, the 3D image providing apparatus provides a 3D imageto the viewer based on the detected eye location. As described above,the 3D image providing apparatus may operate as a viewpoint trackingautostereoscopic 3D display, and thus may render the 3D image based onthe eye location of the viewer. When a same content is to be output, aconfiguration of a panel image to be output through a display panel mayvary based on the eye location of the viewer. That is, based on the eyelocation of the viewer, whether an image pixel value of a left-viewimage or an image pixel value of a right-view image is allocated to acurrent display pixel may be determined. Rendering of the 3D image maybe performed separately for each display pixel based on a location of aleft eye of the viewer and a location of a right eye of the viewer, andon a ray direction of a ray output from each display pixel. Hereinafter,how the 3D image is provided by the 3D image providing apparatus will bedescribed in greater detail with reference to FIG. 4.

FIG. 4 is a flowchart illustrating a method of providing a 3D image by a3D image providing apparatus according to an example embodiment.

Referring to FIG. 4, in operation 410, the 3D image providing apparatusdetermines an image pixel value corresponding to a display pixel of adisplay panel. The 3D image providing apparatus allocates an image pixelvalue of one of a left-view image and a right-view image to each displaypixel based on a detected eye location. For example, when a raydirection of a ray output from a display pixel, or a ray direction of adisplay pixel, is closer to a location of a left eye of a viewer than alocation of a right eye of the viewer, the 3D image providing apparatusmay allocate the image pixel value of the left-view image to the displaypixel. Conversely, when the ray direction of the display pixel is closerto the location of the right eye than the location of the left eye, the3D image providing apparatus may allocate the image pixel value of theright-view image to the display pixel.

According to an example, to further reduce a crosstalk component from a3D image, a series of image preprocessing processes may be performedfirst. For example, the 3D image providing apparatus may adjust aluminance range of image pixel values of the left-view image and theright-view image that are input images, and correct a crosstalk toreduce an offset crosstalk component. Such a process will be describedin greater detail with reference to FIG. 5.

In operation 420, the 3D image providing apparatus determines aluminance weight corresponding to the display pixel based on a raydirection of the display pixel and the eye location detected inoperation 310. For example, when the ray direction of the display pixelis closer to the location of the left eye or the right eye, the 3D imageproviding apparatus may allocate a greater luminance weight to thedisplay pixel. Conversely, when the ray direction of the display pixelis farther away from the location of the left eye and the location ofthe right eye, or the ray direction of the display pixel is closer to amiddle location between the left eye and the right eye, the 3D imageproviding apparatus may allocate a lower luminance weight to the displaypixel.

According to an example embodiment, the 3D image providing apparatus maydetermine the luminance weight based on at least one of a firstreference value indicating a closeness between the ray direction of thedisplay pixel and the location of the left eye, and a second referencevalue indicating a closeness between the ray direction of the displaypixel and the location of the right eye. The first reference valuecorresponds to a difference between the ray direction of the displaypixel and a direction from the display pixel towards the left eye of theviewer, and the second reference value corresponds to a differencebetween the ray direction of the display pixel and a direction from thedisplay pixel towards the right eye of the viewer. For example, thefirst reference value may be determined based on an angle ⊖L between theray direction of the display pixel and a direction of a line from thedisplay pixel towards the location of the left eye or a distance dLbetween the ray direction, which corresponds to a distance between apass-through point through which the ray direction passes on a straightline passing through a center location of the left eye and a centerlocation of the right eye, and the location of the left eye. The secondreference value may be determined based on an angle ⊖R between the raydirection of the display pixel and a direction of a line from thedisplay pixel towards the location of the right eye or a distance dRbetween the ray direction and the location of the right eye. As thedistance between the ray direction of the display pixel and the locationof the left eye decreases, the first reference value may decrease. Asthe distance between the ray direction of the display pixel and thelocation of the right eye decreases, the second reference value maydecrease.

According to an example embodiment, the 3D image providing apparatus maydetermine, to be the luminance weight corresponding to the displaypixel, among predefined different luminance weights based on at leastone of the first reference value or the second reference value. Forexample, when the first reference value is included in a first referencevalue range based on the location of the left eye or the secondreference value is included in a second reference value range based onthe location of the right eye, the 3D image providing apparatus maydetermine a first luminance weight to be the luminance weightcorresponding to the display pixel. Conversely, when the first referencevalue is not included in the first reference value range and the secondreference value is not included in the second reference value range, the3D image providing apparatus may determine a second luminance weight tobe the luminance weight corresponding to the display pixel. Here, amagnitude of the first reference value range may be equal to a magnitudeof the second reference value range, and the first luminance weight maybe greater than the second luminance weight. Also, the first referencevalue being included in the first reference value range or the secondreference value being included in the second reference value range mayindicate that the ray direction of the display pixel is closer to theleft eye or the right eye. In such a case, a greater luminance weightmay be allocated to the display pixel.

For example, a reference value may correspond to a difference indistance |dR−dL| between a distance from a ray direction and a locationto a left eye from a ray direction and a distance to a right eye fromthe ray. When |dR−dL| is within a range from 0 to an interpupillarydistance (IPD), a corresponding luminance weight may be from a minimumvalue 50%, when it is 0 and gradually increase to 100% from point wherethe distance is IPD/2. Similarly, a luminance weight may be appliedbased on a change in a difference between the angles |ΘR−ΘL|. When a100% luminance weight is allocated, an image pixel value with anoriginal luminance may be output through a corresponding display pixelwithout reducing the luminance of the image pixel value.

Also, the first reference value not being included in the firstreference value range, and the second reference value not being includedin the second reference value range may indicate that the ray directionof the display pixel is far away from the left eye and the right eye. Insuch a case, a smaller luminance weight may be allocated to the displaypixel. For example, when a 50% luminance weight is allocated, aluminance of an image pixel value may be output through a correspondingdisplay pixel by reducing the luminance of the image pixel value to 50%.For example, when the ray direction of the display pixel is close to themiddle location between the left eye and the right eye, a smallerluminance weight may be allocated. Here, the luminance weight may bedetermined based on a magnitude of the first reference value or thesecond reference value. For example, the luminance weight may bedetermined to be one of predefined values, for example, 50%, 60%, . . ., 90%, and 100%, or determined based on a predefined function. Throughsuch a process, a crosstalk may be reduced by reducing or preventing theright-view image from being viewed by the left eye or the left-viewimage from being viewed by the right eye.

In operation 430, the 3D image providing apparatus applies the luminanceweight determined in operation 420 to the image pixel valuecorresponding to the display pixel. A luminance of the image pixel valueto be output through the display pixel may be adjusted based on theluminance weight applied to the image pixel value. For example, in acase of a 100% luminance weight, an image pixel value with an originalluminance may be output. In a case of a luminance weight less than 100%,an image pixel value with a luminance less than an original luminancemay be output.

In operation 440, the 3D image providing apparatus outputs the imagepixel value to which the luminance weight is applied through the displaypixel. As described above, the 3D image providing apparatus maydetermine a luminance weight corresponding to each display pixel andoutput an image pixel value to which the determined luminance weight isapplied through a corresponding display pixel to output a 3D image witha reduced crosstalk component.

FIG. 5 is a flowchart illustrating a method of determining an imagepixel value to be allocated to a display pixel according to an exampleembodiment. As described hereinafter, a 3D image providing apparatus mayreceive a luminance scaling value and a crosstalk correction value asparameters, and correct an offset crosstalk using the parameters.

Referring to FIG. 5, in operation 510, the 3D image providing apparatusadjusts a luminance range of image pixels of a left-view image and aluminance range of image pixels of a right-view image based on apredefined luminance scaling value to maintain a margin range. Accordingto an example embodiment, the luminance scaling value may includeinformation associated with at least one of a minimum luminance value ora maximum luminance value of the image pixels. The 3D image providingapparatus may scale the luminance range of the image pixels based on theminimum luminance value and/or the maximum luminance value in theluminance scaling value.

For example, when the luminance range of the image pixels is 0 to 255,the 3D image providing apparatus may scale the luminance range of theimage pixels to be 20 to 230 based on the luminance scaling value. Afterthe scaling is performed, the minimum luminance value of the imagepixels may be adjusted to be greater than or equal to 20, and themaximum luminance value of the image pixels may be adjusted to be lessthan or equal to 230. Such a scaling may be performed to secure a marginof image pixel values in a following process of adjusting an image pixelvalue.

In operation 520, the 3D image providing apparatus adjusts a luminancevalue of each of the image pixels of the left-view image and theright-view image with the luminance range adjusted in operation 510based on a predefined crosstalk correction value. The 3D image providingapparatus may extract a luminance value by converting an image pixelvalue of each of the image pixels in a red, green, blue (RGB) colorspace to a luminance space through gamma decoding, and subtract acrosstalk component from the luminance value by applying the crosstalkcorrection value to the luminance value. For example, when thepredefined crosstalk correction value is 3%, a luminance valuecorresponding to 3% of an original luminance value may be subtractedfrom the luminance value by applying the crosstalk correction value tothe luminance value. The 3D image providing apparatus may then convertagain, from the luminance space to the RGB color space, the image pixelvalue to which the crosstalk correction value is applied through gammaencoding. Through operations 510 and 520, the luminance range of theimage pixels of the left-view image and the right-view image may bescaled, and the luminance value may be adjusted to correct a crosstalk.

In operation 530, the 3D image providing apparatus determines which of alocation of a right eye of a viewer and a location of a left eye of theviewer is closer to a ray direction of a display pixel. In operation540, in response to the pass-through point of the ray direction of thedisplay pixel being closer to the location of the left eye than thelocation of the right eye, the 3D image providing apparatus allocates,to the display pixel, an image pixel value of the left-view image withthe luminance value adjusted in operation 520. In operation 550, inresponse to the ray direction of the display pixel being closer to thelocation of the right eye than the location of the left eye, the 3Dimage providing apparatus allocates, to the display pixel, an imagepixel value of the right-view image with the luminance value adjusted inoperation 520. The 3D image providing apparatus may allocate an imagepixel value to each of all display pixels, and generate a panel imagebased on the allocation.

FIGS. 6A and 6B are diagrams illustrating examples of determining afirst reference value and a second reference value based on a raydirection of a display pixel and an eye location according to an exampleembodiment.

Referring to FIG. 6A, a ray output from a display pixel 615 included ina display panel 610 proceeds in a ray direction 617 by a 3D opticaldevice. The ray direction 617 of the display pixel 615 may be defined bya structural characteristic of the 3D optical device. When a location ofa left eye 620 of a viewer and a location of a right eye 625 of theviewer are determined, a 3D image providing apparatus determines a firstreference value indicating a closeness between the ray direction 617 ofthe display pixel 615 and the location of the left eye 620, and a secondreference value indicating a closeness between the ray direction 617 ofthe display pixel 615 and the location of the right eye 625.

For example, the 3D image providing apparatus determines a pass-throughpoint through which the ray direction 617 passes on a straight line 630passing through a center location of the left eye 620 and a centerlocation of the right eye 625. The 3D image providing apparatusdetermines a distance 640 between a location of the pass-through pointand the location of the left eye 620 to be the first reference value,and a distance 645 between the location of the pass-through point andthe location of the right eye 625 to be the second reference value. The3D image providing apparatus compares the distance 640 and the distance645 and determines whether the ray direction 617 of the display pixel615 is closer to the left eye 620 or the right eye 625. As illustratedin FIG. 6A, the distance 640 is less than the distance 645, and thus the3D image providing apparatus determines that the ray direction 617 iscloser to the left eye 620.

Referring to FIG. 6B, each of the first reference value and the secondreference value may be determined based on an angle difference. Asillustrated, an angle 660 formed between a direction of a line 650proceeding from the display pixel 615 towards the location of the lefteye 620 and the ray direction 617 of the ray output from the displaypixel 615 is determined to be the first reference value. In addition, anangle 665 formed between a direction of a line 655 proceeding from thedisplay pixel 615 towards the location of the right eye 625 and the raydirection 617 of the ray output from the display pixel 615 is determinedto be the second reference value. The 3D image providing apparatuscompares the angle 660 and the angle 665, and determines whether the raydirection 617 of the display pixel 615 is closer to the left eye 620 orthe right eye 625. As illustrated in FIG. 6B, the angle 660 is less thanthe angle 665, and thus the 3D image providing apparatus determines thatthe ray direction 617 is closer to the left eye 620.

FIG. 7 is a diagram illustrating an example of merging viewpointinformation in a viewpoint tracking autostereoscopic 3D display deviceaccording to an example embodiment.

FIG. 7 illustrates a viewing direction-based luminance profile 705indicated for each of viewing directions, and a luminance profile 717 inwhich luminance profiles of the viewing directions are merged into aluminance profile of a left viewpoint and a luminance profile of a rightviewpoint. In the luminance profile 705, a broken line 710 indicates aluminance distribution characteristic of each of viewing directions towhich a left-view image is output, and a solid line 715 indicates aluminance distribution characteristic of each of viewing directions towhich a right-view image is output. The luminance profile 717 isobtained by merging the luminance distribution characteristics indicatedin the luminance profile 705 based on the left viewpoint and the rightviewpoint. In the luminance profile 717, “A” indicates a location of aleft eye of a viewer, and “B” indicates a location of a right eye of theviewer. By merging viewpoint information based on the location of theleft eye and the location of the right eye, a crosstalk may be reduced.However, referring to the luminance profile 717, a luminance component725 of the right-view image, in addition to a luminance component 720 ofthe left-view image output to various viewing directions, may also reachthe left eye. Here, a luminance component 730 of the right-view imagethat reaches the location of the left eye may correspond to a crosstalkcomponent. Also, when the luminance component 720 of the left-view imagereaches the right eye, a luminance component 735 of the left-view imagethat reaches the location of the right eye may also correspond to acrosstalk component. Such crosstalk components may be reduced using aluminance weight described herein.

FIGS. 8A and 8B, and FIGS. 9A and 9B are diagrams illustrating examplesof determining a luminance weight based on an eye location of a vieweraccording to an example embodiment.

Referring to FIG. 8A, a 3D image output from a display panel 810 reachesa left eye 820 and a right eye 825 of a viewer. A 3D image providingapparatus allocates an image pixel value of a left-view image or animage pixel value of a right-view image to a display pixel based on aray direction of a ray output from each of display pixels of the displaypanel 810 and on a location of the left eye 820 and a location of theright eye 825. FIG. 8A also illustrates a luminance profile 830 of theleft-view image merged at the location of the left eye 820 and aluminance profile 835 of the right-view image merged at the location ofthe right eye 825. As described with reference to FIG. 7, an unintendedviewpoint image may be transmitted to each of the location of the lefteye 820 and the location of the right eye 825, and thus a crosstalk mayoccur.

Referring to FIG. 8B, the 3D image providing apparatus may reduce such acrosstalk by applying a luminance weight to an image pixel value to beallocated to each of display pixels included in the display panel 810.The 3D image providing apparatus may determine a magnitude of aluminance weight corresponding to each of the display pixels based on aray direction of each of the display pixels and the locations of theleft eye 820 and the right eye 825. When mapping an image pixel value toa display pixel, the 3D image providing apparatus may compare a raydirection of the display pixel and the locations of the left eye 820 andthe right eye 825, and determine a magnitude of a luminance weight to beapplied to the image pixel value. For example, when the ray direction iscloser to the location of the left eye 820 or the right eye 825, the 3Dimage providing apparatus may determine the magnitude of the luminanceweight to be 100% such that an original luminance value of the imagepixel value is to be maintained. Conversely, when the ray direction isfarther away from the location of the left eye 820 or the right eye 825,the 3D image providing apparatus may decrease the luminance value of theimage pixel value by applying a relatively low luminance weight.

According to an example embodiment, the 3D image providing apparatus maydetermine a first reference value and a second reference value based ona ray direction of a display pixel and each of the locations of the lefteye 820 and the right eye 825. When the first reference value isincluded in a first reference value range based on the location of theleft eye 820, or the second reference value is included in a secondreference value range based on the location of the right eye 825, a 100%luminance weigh may be applied to an image pixel value to be allocatedto the display pixel. However, when the first reference value is notincluded in the first reference value range and the second referencevalue is not included in the second reference value range, a luminanceweight less than 100%, for example, 50%, may be applied to the imagepixel value, and thus the image pixel value with a luminance value lessthan an original luminance value may be output. Thus, the 3D imageproviding apparatus may determine a luminance weight corresponding toeach of the display pixels based on a ray direction of each of thedisplay pixels and the locations of the left eye 820 and the right eye825. The 3D image providing apparatus may then apply the determinedluminance weight to an image pixel value to be output through each ofthe display pixels such that an influence of a display pixel that doesnot directly project an image to the left eye 820 and the right eye 825may be reduced and a crosstalk component may also be reduced. FIG. 8Balso illustrates a luminance weight 850 that is applied to each of thedisplay pixels, and a luminance profile 840 of the left-view imagemerged at the location of the left eye 820 and a luminance profile 845of the right-view image merged at the location of the right eye 825. Bycomparing the luminance profiles 840 and 845 illustrated in FIG. 8B andthe luminance profiles 830 and 835 illustrated in FIG. 8A, it isverified that a crosstalk component is reduced at each of the locationsof the left eye 820 and the right eye 825 by applying the luminanceweight 850.

FIG. 9A illustrates a relative luminance magnitude of an image for eachof viewing directions that is viewed by a right eye of a viewer of anautostereoscopic 3D display device without applying a luminance weight.Referring to FIG. 9A, it is estimated that the right eye is locatedclose to a viewing direction 33. The viewing directions used herein maybe obtained by classifying a viewing region based on a location of theautostereoscopic 3D display device into a plurality of viewingdirections in which the viewer may view a 3D image output from theautostereoscopic 3D display device. Display pixels corresponding toviewing directions 23 through 45 that are closer to the right eye thanthe left eye may output an image pixel value of a right-view image.Display pixels corresponding to viewing directions 1 through 22 that arecloser to the left eye than the right eye may output an image pixelvalue of a left-view image. In addition to a luminance component 910 ofthe right-view image, a portion of a luminance component 920 of theleft-view image may also be viewed by the right eye. The luminancecomponent 920 of the left-view image that is viewed by the right eye maycause a crosstalk. Such a crosstalk may be reduced using a luminanceweight described herein.

FIG. 9B illustrates a magnitude of a luminance weight to be applied foreach of viewing directions, and a magnitude of a luminance component ofa right-view image and a magnitude of a luminance component of aleft-view image for each of the viewing directions that are viewed at alocation of a right eye when the luminance weight is applied. FIG. 9Balso illustrates a graph 930 indicating a continuous magnitude of aluminance weight to be applied to display pixels based on a raydirection. FIG. 9B also illustrates a luminance component 915 of theright-view image in each viewing direction that is viewed at thelocation of the right eye, and a luminance component 925 of theleft-view image in each viewing direction that viewed at the location ofthe right eye, when the luminance weight is applied. When a raydirection of a display pixel is close to the left eye or the right eye,a 100% luminance weight may be applied. When the ray direction is arounda middle location between the left eye and the right eye, or a viewingdirection 22, a luminance weight with a low magnitude, for example, 50%,may be applied. To display pixels located between a location at which aray direction is close to the left eye or the right eye and the middlelocation between the left eye and the right eye, a linearly decreasingluminance weight may be applied. In addition, a luminance weight with alow magnitude may also be applied to display pixels having raydirections that are farther away from the locations of the left eye andthe right eye. By applying such a luminance weight, the luminancecomponent 920 of the left-view image that is viewed by the right eye maybe reduced, and thus the crosstalk may also be reduced.

FIG. 10 is a diagram illustrating a 3D image rendering apparatusaccording to an example embodiment.

Referring to FIG. 10, a 3D image rendering apparatus 1000 may generate apanel image to be transmitted to a display panel based on inputinformation. The input information may include, for example, an eyelocation value detected by an eye location detector, a luminance scalingvalue, an image pixel value of a left-view image and an image pixelvalue of a right-view image, and a crosstalk correction value. Theluminance scaling value and the crosstalk correction value may beadjusted in magnitude thereof while a viewer is viewing a resultingimage. The 3D image rendering apparatus 100 may generate the panel imagewith a reduced crosstalk component by applying a luminance weight to animage pixel value based on a ray direction of a display panel andlocations of both eyes of the viewer. The 3D image rendering apparatus1000 may perform such an image processing on each of image pixels of thepanel image, and the image processing may be performed, in parallel, onthe image pixels.

As illustrated in FIG. 10, the 3D image rendering apparatus 1000includes a luminance scaler 1010, a gamma decoder 1020, a crosstalkcorrector 1030, a gamma encoder 1040, a renderer 1050, and a luminanceweight applier 1060. The 3D image rendering apparatus 1000 may beincluded in a 3D image providing apparatus described herein.

The luminance scaler 1010 may adjust a luminance range of image pixelvalues of an entire left-view image and a luminance range of image pixelvalues of an entire right-view image based on a predefined luminancescaling value. According to an example embodiment, the luminance scaler1010 may linearly convert the luminance ranges based on a minimumluminance value and a maximum luminance value that are defined in theluminance scaling value. Through such a process described in theforegoing, a luminance range of image pixels may be reduced.

The gamma decoder 1020 may perform gamma decoding to convert an imagepixel value with the adjusted luminance range in an RGB color space to aluminance space. The gamma decoding may be performed because a crosstalkcomponent is added to both eyes of the viewer based on a luminance valueof a display pixel, not on the image pixel value.

The crosstalk corrector 1030 may correct a crosstalk to adjust aluminance value of each of image pixels of the left-view image and theright-view image based on the crosstalk correction value, which isinformation of a magnitude of a crosstalk desired to be reduced. Thecrosstalk corrector 1030 may subtract a luminance value corresponding tothe crosstalk correction value from a luminance value of each of theimage pixels. For example, when the crosstalk correction value is 3%,the crosstalk corrector 1030 may subtract 3% from a luminance value ofeach of all the image pixels. Thus, an offset crosstalk component thatmay cause the crosstalk may be reduced.

The gamma encoder 1040 may convert, from the luminance space to the RGBcolor space through gamma encoding, the image pixel value on which thecrosstalk correction is performed. Thus, an image pixel value of a colorvalue to which the crosstalk correction value is applied may beobtained. According to an example, when the gamma decoding and the gammaencoding are performed on each image pixel, a gamma curve of each of RGBcolors may be used or a single gamma curve may be used to reduce a colordistortion.

The renderer 1050 may allocate the image pixel value on which thecrosstalk correction is performed to each display pixel based onrespective eye location values of both eyes of the viewer. The renderer1050 may determine whether an image pixel value to be displayed by eachdisplay pixel in a 3D rendering process is of the left-view image or theright-view image, based on a ray direction of each display pixel and thelocations of the left eye and the right eye. When a ray direction of adisplay pixel is closer to the left eye than the right eye, the renderer1050 may allocate the image pixel value of the left-view image to thedisplay pixel. Conversely, when the ray direction is closer to the righteye than the left eye, the renderer 1050 may allocate the image pixelvalue of the right-view image to the display pixel. To estimate acloseness between a ray direction of a display pixel and the location ofthe left eye, the renderer 1050 may compare a difference between the raydirection of the display pixel and a direction from the display pixeltowards the left eye, and a difference between the ray direction of thedisplay pixel and a direction from the display pixel towards the righteye.

The luminance weight applier 1060 may determine a luminance weightcorresponding to each display pixel based on a ray direction of eachdisplay pixel and an eye location value, and apply the determinedluminance weight to an image pixel value corresponding to each displaypixel. According to an example embodiment, the luminance weight mayincrease when a ray direction is close to one of the eyes, and decreasewhen the ray direction is far away from both eyes or close to a middlelocation between the eyes. For example, when a ray direction of adisplay pixel is close to the location of the left eye or the right eye,the luminance weight applier 1060 may allocate a luminance weight to thedisplay pixel to maintain an original luminance value of a correspondingimage pixel value. When a ray direction of a display pixel is far awayfrom the locations of the left eye and the right eye, or close to themiddle location between the left eye and the right eye, the luminanceweight applier 1060 may allocate a luminance weight to the display pixelto reduce a luminance value of a corresponding image pixel value.

A difference between a ray direction of a display pixel and a directionfrom the display pixel towards the left eye, and a difference betweenthe ray direction and a direction from the display pixel towards theright eye being similar to each other may indicate that the raydirection of the display pixel is not close to either the left eye orthe right eye. In addition, an image pixel value to be output by thedisplay pixel may contribute less to a luminance component of a 3D imageto be viewed by the viewer, and it is more likely that the image pixelvalue would be a crosstalk component. Thus, by decreasing a luminancevalue of the image pixel value by applying a relatively low luminanceweight, such a crosstalk component may be reduced. Conversely, adifference between the ray direction of the display pixel and thedirection from the display pixel towards the left eye, and a differencebetween the ray direction and the direction from the display pixeltowards the right eye being not similar to each other may indicate thatthe ray direction of the display pixel is close to one of the left eyeand right eye. In addition, it is highly likely that the image pixelvalue to be output by the display pixel may contribute more to aluminance component of the 3D image to be viewed by the viewer. In sucha case, a luminance value of the image pixel value may be equal to orsimilar to an original luminance value based on a relatively highluminance weight.

Thus, the luminance weight applier 1060 may generate a panel image witha reduced crosstalk component by applying, to an image pixel valuecorresponding to each display pixel, a luminance weight allocated toeach display pixel.

FIG. 11 is a diagram illustrating a configuration of a 3D imageproviding apparatus according to an example embodiment.

Referring to FIG. 11, a 3D image providing apparatus 1100 includes aneye location detector 1110, a processor 1120, a memory 1130, and adisplay panel 1140.

The eye location detector 1110 may detect an eye location of a viewer.The eye location detector 1110 may include a camera that is included inthe 3D image providing apparatus 1100 and configured to track aviewpoint of the viewer in real time. According to an exampleembodiment, the eye location detector 1110 may detect feature pointscorresponding to an eye of the viewer from an image captured by thecamera, and determine a location of the eye of the viewer based onlocations of the detected feature points. For example, the eye locationdetector 1110 may determine a center location of feature pointscorresponding to a pupil of a left eye of the viewer to be a location ofthe left eye, and a center location of feature points corresponding to apupil of a right eye of the viewer to be a location of the right eye.The eye location detector 1110 may also determine the location of theleft eye and the location of the right eye using a neural network thatis trained to output each of the location of the left eye and thelocation of the right eye from an image including a face region of theviewer. However, example embodiments are not limited thereto, and thedetecting of the eye location is not limited to the examples describedin the foregoing, and the eye location detector 1110 may detect the eyelocation of the viewer using other various methods. The eye locationdetector 1110 may then transmit an image captured or the calculated eyelocation to the processor 1120.

The processor 1120 may control the 3D image providing apparatus 1100,and perform operations described with reference to FIGS. 1 through 10.For example, the processor 1120 may perform operations described withreference to FIGS. 3 through 5. The processor 1120 may generate a panelimage based on the detected eye location. The processor 1120 mayconfigure the panel image based on images of different viewpoints suchthat the images of the different viewpoints may be viewed by the lefteye and the right eye, respectively, of the viewer. Here, the processor1120 may determine a luminance weight to be allocated to each displaypixel based on a ray direction of a ray output from each display pixeland locations of both eyes of the viewer, and generate the panel imagewith a reduced crosstalk component by applying the determined luminanceweight to an image pixel value.

In addition, the processor 1120 may perform functions of components ofthe 3D image rendering apparatus 1000 described with reference to FIG.10. The processor 1120 may be variously embodied in a single processor,a multiprocessor, a hardware accelerator (HWA), a graphic processingunit (GPU), or a combination thereof.

The memory 1130 may store viewpoint images, for example, a stereo imageof a left-view image and a right-view image, a panel image, instructionsfor operations of the processor 1120, and data such as variousfunctions, equations, and operation results. In addition, the memory1130 may transmit related data to the processor 1120, and other datastored in the memory 1130 to the processor 1120.

The display panel 1140 may convert the panel image generated by theprocessor 1120 to a 3D image, and output the 3D image. The display panel1140 may include a 3D optical device to convert the panel image in atwo-dimensional (2D) form to the 3D image, for example, a parallaxbarrier and a lenticular lens.

FIG. 12 is a flowchart illustrating a 3D image providing methodaccording to an example embodiment.

Referring to FIG. 12, in operation 1210, a 3D image providing apparatusdetects an eye location of a viewer. The 3D image providing apparatusdetermines the eye location of the viewer by capturing an image in frontof the 3D image providing apparatus using a camera, and analyzing thecaptured image. For example, the 3D image providing apparatus may detecta feature point associated with an eye region in the image captured bythe camera, and determine the eye location of the viewer based on alocation of the detected feature point. In operation 1220, the 3D imageproviding apparatus adjusts a luminance range of image pixels of aleft-view image and a luminance range of image pixels of a right-viewimage based on a predefined luminance scaling value to maintain a marginrange. In operation 1230, the 3D image providing apparatus adjusts aluminance value of each of the image pixels of the left-view image andthe right-view image with the luminance range adjusted in operation 510based on a predefined crosstalk correction value.

In operation 1240, the 3D image providing apparatus determines aluminance weight corresponding to the display pixel based on a raydirection of the display pixel and the eye location detected inoperation 1210. For example, when the ray direction of the display pixelis closer to the location of the left eye or the right eye, the 3D imageproviding apparatus may allocate a greater luminance weight to thedisplay pixel. Conversely, when the ray direction of the display pixelis farther away from the location of the left eye and the location ofthe right eye, or the ray direction of the display pixel is closer to amiddle location between the left eye and the right eye, the 3D imageproviding apparatus may allocate a lower luminance weight to the displaypixel.

In operation 1250, the 3D image providing apparatus applies theluminance weight determined in operation 1240 to the image pixel valuecorresponding to the display pixel. A luminance of the image pixel valueto be output through the display pixel may be adjusted based on theluminance weight applied to the image pixel value. For example, in acase of a 100% luminance weight, an image pixel value with an originalluminance may be output.

In operation 1260, the 3D image providing apparatus outputs the imagepixel value to which the luminance weight is applied through the displaypixel. As described above, the 3D image providing apparatus maydetermine a luminance weight corresponding to each display pixel andoutput an image pixel value to which the determined luminance weight isapplied through a corresponding display pixel to output a 3D image witha reduced crosstalk component.

The apparatuses and units described herein may be implemented usinghardware components and software components. For example, the hardwarecomponents may include microphones, amplifiers, band-pass filters, audioto digital convertors, non-transitory computer memory and processingdevices. A processing device may be implemented using one or moregeneral-purpose or special purpose computers, such as, for example, aprocessor, a controller and an arithmetic logic unit, a digital signalprocessor, a microcomputer, a field programmable array, a programmablelogic unit, a microprocessor or any other device capable of respondingto and executing instructions in a defined manner. The processing devicemay run an operating system (OS) and one or more software applicationsthat run on the OS. The processing device also may access, store,manipulate, process, and create data in response to execution of thesoftware. For purpose of simplicity, the description of a processingdevice is used as singular, however, a processing device may includemultiple processing elements and multiple types of processing elements.For example, a processing device may include multiple processors or aprocessor and a controller. In addition, different processingconfigurations are possible, such a parallel processors.

The software may include a computer program, a piece of code, aninstruction, or some combination thereof, to independently orcollectively instruct or configure the processing device to operate asdesired. Software and data may be embodied permanently or temporarily inany type of machine, component, physical or virtual equipment, computerstorage medium or device, or in a propagated signal wave capable ofproviding instructions or data to or being interpreted by the processingdevice. The software also may be distributed over network coupledcomputer systems so that the software is stored and executed in adistributed fashion. The software and data may be stored by one or morenon-transitory computer readable recording mediums. The non-transitorycomputer readable recording medium may include any data storage devicethat can store data which can be thereafter read by a computer system orprocessing device. Examples of the non-transitory computer readablerecording medium include read-only memory (ROM), random-access memory(RAM), CD-ROMs, magnetic tapes, floppy disks, optical data storagedevices. Also, functional programs, codes, and code segments thataccomplish the examples disclosed herein can be easily construed byprogrammers skilled in the art to which the examples pertain based onand using the flow diagrams and block diagrams of the figures and theircorresponding descriptions as provided herein.

While this disclosure includes specific examples, it will be apparent toone of ordinary skill in the art that various changes in form anddetails may be made in these examples without departing from the spiritand scope of the claims and their equivalents. The examples describedherein are to be considered in a descriptive sense only, and not forpurposes of limitation. Descriptions of features or aspects in eachexample are to be considered as being applicable to similar features oraspects in other examples. Suitable results may be achieved if thedescribed techniques are performed in a different order, and/or ifcomponents in a described system, architecture, device, or circuit arecombined in a different manner and/or replaced or supplemented by othercomponents or their equivalents. Therefore, the scope of the disclosureis defined not by the detailed description, but by the claims and theirequivalents, and all variations within the scope of the claims and theirequivalents are to be construed as being included in the disclosure.

What is claimed is:
 1. A three-dimensional (3D) image providing methodcomprising: detecting an eye location of a viewer, the eye locationcomprising a location of a right eye of the viewer and a location of aleft eye of the viewer; and providing a 3D image based on the detectedeye location, wherein the providing of the 3D image comprises:determining an image pixel value corresponding to a display pixelincluded in a display panel; determining a luminance weightcorresponding to the display pixel based on a ray direction of a rayoutput from the display pixel and the detected eye location; applyingthe determined luminance weight to the image pixel value correspondingto the display pixel; and outputting, through the display pixel, theimage pixel value with the determined luminance weight applied thereto,wherein the determining of the luminance weight further comprisesdetermining the luminance weight based on at least one of a firstreference value corresponding to a distance between a pass-through pointof the ray and the location of the left eye of the viewer, or a secondreference value corresponding to a distance between the pass-throughpoint of the ray and the location of the right eye of the viewer, andwherein the pass-through point of the ray is a location where the raycrosses a line passing through the location of the left eye of theviewer and the location of the right eye of the viewer, and thepass-through point of the ray is spaced apart from the left eye of theviewer and the right eye of the viewer.
 2. The 3D image providing methodof claim 1, wherein the determining of the luminance weight comprisesdetermining a predefined luminance weight among a plurality ofpredefined luminance weights to be the luminance weight, based on the atleast one of the first reference value or the second reference value. 3.The 3D image providing method of claim 1, wherein the determining of theluminance weight comprises based on the first reference value beingincluded in a first reference value range that is based on the locationof the left eye or the second reference value being included in a secondreference value range that is based on the location of the right eye,determining a first luminance weight to be the luminance weightcorresponding to the display pixel.
 4. The 3D image providing method ofclaim 3, wherein the determining of the luminance weight comprises basedon the first reference value being outside of the first reference valuerange and the second reference value being outside of the secondreference value range, determining a second luminance weight to be theluminance weight corresponding to the display pixel, and wherein thefirst luminance weight is greater than the second luminance weight. 5.The 3D image providing method of claim 3, wherein a magnitude of thefirst reference value range is equal to a magnitude of the secondreference value range.
 6. The 3D image providing method of claim 1,wherein the first reference value corresponds to a difference betweenthe ray direction and a direction of a line from the display pixeltowards the location of the left eye, and the second reference valuecorresponds to a difference between the ray direction and a direction ofa line from the display pixel towards the location of the right eye. 7.The 3D image providing method of claim 6, wherein the first referencevalue is determined based on an angle between the ray direction and thedirection of the line from the display pixel towards the location of theleft eye, or the distance between the pass-through point of the raydirection and the location of the left eye, and the second referencevalue is determined based on an angle between the ray direction and thedirection of the line from the display pixel towards the location of theright eye, or the distance between the pass-through point of the raydirection and the location of the right eye.
 8. The 3D image providingmethod of claim 1, wherein a luminance of the image pixel value to beoutput through the display pixel is adjusted based on the luminanceweight to be applied to the image pixel value.
 9. The 3D image providingmethod of claim 1, wherein the determining of the image pixel valuecomprises allocating, to the display pixel, an image pixel value of oneof a left-view image and a right-view image, based on the detected eyelocation.
 10. The 3D image providing method of claim 9, wherein thedetermining of the image pixel value further comprises: adjusting a leftluminance range of image pixels of the left-view image and a rightluminance range of image pixels of the right-view image, based on apredefined luminance scaling value; and adjusting a luminance value ofeach of the image pixels of the left-view image with the adjusted leftluminance range and a luminance value of each of the image pixels of theright-view image with the adjusted right luminance range, based on apredefined crosstalk correction value.
 11. The 3D image providing methodof claim 10, wherein the determining of the image pixel value furthercomprises: based on the distance between the pass-through point of theray direction and a location of the left eye of the viewer being smallerthan the distance between the pass-through point of the ray directionand a location of the right eye of the viewer, allocating the imagepixel value of the left-view image with the adjusted left luminancevalue to the display pixel; and based on the distance between thepass-through point of the ray direction and the location of the righteye being smaller than the distance between the pass-through point ofthe ray direction and the location of the left eye, allocating the imagepixel value of the right-view image with the adjusted right luminancevalue to the display pixel.
 12. A non-transitory computer-readablestorage medium storing instructions that, when executed by a processor,cause the processor to perform the 3D image providing method of claim 1.13. A three-dimensional (3D) image providing apparatus comprising: aneye location detector configured to detect an eye location of a viewer,the eye location comprising a location of a right eye of the viewer anda location of a left eye of the viewer; a processor configured togenerate a panel image based on the detected eye location; and a displaypanel configured to output a 3D image based on the generated panelimage, wherein the processor is further configured to: determine aluminance weight corresponding to a display pixel of the display panelbased on a ray direction of a ray output from the display pixel and thedetected eye location; apply the determined luminance weight to an imagepixel value corresponding to the display pixel; and generate the panelimage based on the image pixel value with the luminance weight appliedthereto, wherein the processor is further configured to determine theluminance weight based on at least one of a first reference valuecorresponding to a distance between a pass-through point of the ray andthe location of the left eye of the viewer, or a second reference valuecorresponding to a distance between the pass-through point of the rayand the location of the right eye of the viewer, and wherein thepass-through point of the ray is a location where the ray crosses a linepassing through the location of the left eye of the viewer and thelocation of the right eye of the viewer, and the pass-through point ofthe ray is spaced apart from the left eye of the viewer and the righteye of the viewer.
 14. The 3D image providing apparatus of claim 13,wherein the processor is further configured to determine a predefinedluminance weight among a plurality of predefined luminance weights to bethe luminance weight corresponding to the display pixel, based on atleast one of the first reference value or the second reference value.15. The 3D image providing apparatus of claim 13, wherein the processoris further configured to adjust a left luminance range of image pixelsof a left-view image and a right luminance range of image pixels of aright-view image, based on a predefined luminance scaling value, andadjust a luminance value of each of the image pixels of the left-viewimage based on the adjusted left luminance range and a luminance valueof each of the image pixels of the right-view image based on theadjusted right luminance range, based on a predefined crosstalkcorrection value.
 16. The 3D image providing apparatus of claim 15,wherein the processor is further configured to allocate an image pixelvalue of the left-view image with the adjusted left luminance value tothe display pixel, based on the distance between the pass-through pointof the ray direction and the location of the left eye of the viewerbeing smaller than the distance between the pass-through point of theray direction and the location of the right eye of the viewer, andallocate an image pixel value of the right-view image with the adjustedright luminance value to the display pixel, based on the distancebetween the pass-through point of the ray direction and the location ofthe right eye being smaller than the distance between the pass-throughpoint of the ray direction and the location of the left eye.
 17. The 3Dimage providing apparatus of claim 13, wherein the display panelcomprises a parallax barrier or a lenticular lens.
 18. Athree-dimensional (3D) image providing method comprising: detecting aright eye location and a left eye location of a viewer; and providing a3D image based on the detected right eye location and the detected lefteye location, wherein the providing of the 3D image comprises:determining an image pixel value corresponding to a display pixelincluded in a display panel by allocating an image pixel value of one ofa left-view image and a right-view image to the display pixel, based onthe detected right eye location and the detected left eye location;adjusting a left luminance range of image pixels of the left-view imageand a right luminance range of image pixels of the right-view image,based on a predefined luminance scaling value; and adjusting a luminancevalue of each of the image pixels of the left-view image with theadjusted left luminance range and a luminance value of each of the imagepixels of the right-view image with the adjusted right luminance range,based on a predefined crosstalk correction value; determining aluminance weight corresponding to the display pixel based on a raydirection of a ray output from the display pixel and the detected righteye location and the detected left eye location; applying the determinedluminance weight to the image pixel value corresponding to the displaypixel; and outputting, through the display pixel, the image pixel valuewith the determined luminance weight applied, wherein the determining ofthe luminance weight further comprises determining the luminance weightbased on at least one of a first reference value corresponding to adistance between a pass-through point of the ray and the detected lefteye location of the viewer, or a second reference value corresponding toa distance between the pass-through point of the ray and the detectedright eye location of the viewer, and wherein the pass-through point ofthe ray is a location where the ray crosses a line passing through thedetected left eye location of the viewer and the detected right eyelocation of the viewer, and the pass-through point of the ray is spacedapart from the detected left eye location of the viewer and the detectedright eye location of the viewer.
 19. The 3D image providing method ofclaim 18, wherein the determining of the image pixel value furthercomprises: based on the distance between the pass-through point of theray direction and the detected left eye location being smaller than thedistance between the pass-through point of the ray direction and thedetected right eye location, allocating the image pixel value of theleft-view image with the adjusted left luminance value to the displaypixel; and based on the distance between the pass-through point of theray direction and the detected right eye location being smaller than thedistance between the pass-through point of the ray direction and thedetected left eye location, allocating the image pixel value of theright-view image with the adjusted right luminance value to the displaypixel.